This invention relates to fifth wheel hitches, and particularly to power elevated, variable height fifth wheel hitches.
The concept of a manually or power operated, variable height fifth wheel hitch is known, as shown for example by U.S. Pat. Nos. 4,671,527; 3,552,774; 3,139,289; 2,928,684; 3,066,956; 3,117,804; 3,287,038; 3,337,170; 4,475,740; 3,253,840; 3,380,758; 3,717,273; 3,810,663 and 4,671,527. Typically the actuators used require significant modification or total redesign of the fifth wheel hitch, to accommodate the lifting structure. The typical conventional hitch, for example, has downwardly projecting reinforcing ribs extending beneath the fifth wheel hitch plate, for strength. This conventional structure provides only a very small space to conceivably insert any actuators for operating a powered, variable height fifth wheel hitch through a vertical range of several inches.
The manual apparatus of U.S. Pat. No. 4,671,527 was developed because of the cost and complexity of previously known power elevated, variable height fifth wheel hitches. However, there are several situations where the physical character of the driver and/or the weight and size of the hitch render manual elevation of the hitch extremely difficult or even impossible.